| 1/00 | Processes or apparatus for liquefying or solidifying gases or gaseous mixtures |
| 1/02 | Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen |
| 3/00 | Processes or apparatus for separating the constituents of gaseous mixtures involving the use of liquefaction or solidification |
| 3/02 | Processes or apparatus for separating the constituents of gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream (F25J 3/08 takes precedence) |
| 3/04 | Processes or apparatus for separating the constituents of gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream (F25J 3/08 takes precedence) for air |
| 3/06 | Processes or apparatus for separating the constituents of gaseous mixtures involving the use of liquefaction or solidification by partial condensation (F25J 3/08 takes precedence; by rectification F25J 3/02) |
| 3/08 | Processes or apparatus for separating the constituents of gaseous mixtures involving the use of liquefaction or solidification Separating gaseous impurities from gases or gaseous mixtures (cold traps B01D 8/00) |
| 5/00 | Arrangements of cold-exchangers or cold-accumulators in separation or liquefaction plants (heat-exchangers F28C, F28D, F28F) |